Pull request overview

Fixes an issue in the Create PR webview flow where rebasing (detached HEAD) could trigger a misleading “Branch does not exist locally” error by ensuring the default compare branch is only set when a valid branch name is available.

Changes:

• Add a guard in setDefaultCompareBranch to no-op when compareBranch or compareBranch.name is missing.
• Remove non-null assertions around compareBranch.name and consistently use the validated branch name.

		this.changeBranch(compareBranch.name, false).then(async titleAndDescription => {
			const params: Partial<CreateParamsNew> = {
				defaultTitle: titleAndDescription.title,
				defaultDescription: titleAndDescription.description,
				compareBranch: compareBranch.name,
				defaultCompareBranch: compareBranch.name,
				warning: await this.existingPRMessage(),
			};
			return this._postMessage({
				command: 'pr.initialize',
				params,
			});
		});